黄土高原藉河流域径流对气候和土地利用变化的响应

目的]揭示黄土高原区中尺度流域径流对气候和土地利用变化的响应规律,为合理解决流域水资源利用和实现水资源的可持续管理提供理论支撑。方法]以黄土高原藉河流域为研究对象,采用Mann-Kendall检验、距平累积曲线、双累积曲线以及分离评判法等方法进行研究。结果](1)1962—2010年藉河流域年降雨呈下降趋势,但下降趋势不显著(p0.05);流域年径流深呈显著下降趋势(p0.001),且在1985年发生减少突变;(2)坡耕地面积减少,梯田面积增加是研究时段内流域土地利用变化的最明显特征。结论]研究时段内土地利用变化是藉河流域径流量减少的主要驱动因素,影响贡献率为90.2%,而气候变化影响较小,贡献率仅为9.8%。

Effects of Climate Variation and Land Use Change on Runoff in Jiehe Watershed of Loess Plateau

Objective] Studying the impacts of climate variation and land use change on annual runoff in meso-scale watershed in order to provide theoretical basis for basin water resources management and land-use planning in this region. Method] Jiehe watershed of Loess Plateau was selected as a research area. Mann-Kendall test, accumulative anomaly curve, double mass curve and separation evaluation method were applied to quantify the respective contribution of climate and land use change to annual runoff of the area in the past 50 years. Results] The annual precipitation among the observed years were not significantly different(p > 0.05), whereas the annual runoff had a significant decreasing trend with a change point occurred in 1979(p < 0.001). Slope farmland declined sharply, terrace area increased rapidly during the study period. Conclusions] Land-use change was the strongest contributor to the reduction in mean annual runoff of Jiehe with 90.2% contribution, and the remaining variation could be interpreted by climate change.